Method and apparatus for regularizing the output of drawing frames of the kind used in textile spinning

ABSTRACT

Method and apparatus for regularizing the output of drawing frames of the type used in the textile spinning industry. At least one of the slivers delivered to the drawing frame is passed through a pair of cylinders having a rotational speed controlled by a measuring signal generated by a measuring element corresponding to the overall cross section of the output of the drawing frame.

United States Patent 1 Felix [111 3,744,093 [451 July 10, 1973,

[ METHOD AND APPARATUS FOR REGULARIZING THE OUTPUT OF DRAWING FRAMES OFTHE KIND USED IN TEXTILE SPINNING [75] Inventor: Ernst Felix, Uster,Switzerland [73] Assignee: Zellweger Ltd., Uster, Switzerland [22]Filed: Nov. 9, 1970 [21] Appl. No.: 87,874

' 301 Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS944,200 12/1963 Great Britain 19/240 Primary Examiner-Dorsey Newton A110N10y-Cr211g and Antonelli 5 7 ABSTRACT Method and apparatus forregularizing the output of drawing frames of the type used in thetextile spinning industry. At least one of the slivers delivered to thedrawing frame is passed through a pair of cylinders having a rotationalspeed controlled by a measuring signal generated by a measuring elementcorresponding to the overall cross section of the output of the drawingframe.

9 Claims, 2 Drawing Figures PRESSURE l0 VOLTAGE m CONVERTERiiillilllmliliiiliflmliii/1"Till g- T llliiilllil 1 7 \"i 1 DRIVE IMEANS I i in: i 1 1 ii i i I PATENTED 1 0 5 3. 744.093

PRESSURE IO VOLTAGE A CONVERTER 1 -ATWNNAEINNN V 7 A DR'VE 6 I MEANS 1 AW A i i M N A A I W FIG. 2

2s V 2| DRIVE DRIVE MEANS 22 l g m MEANS A (A l I! )I BACKGROUND OF THEINVENTION The present invention relates to a method and apparatus forregularizing the output of drawing frames of the kind used in textilespinning.

Among other things, controlled sliver-drawing frames are being used toan ever increasing extent in the automation and qualitative improvementof the textile industry. They produce a more uniform sliver which iseither equivalent to an improvement in quality or enables the productioncycle to be shortened through a reduction in the number of passagesrequired.

Regulated drawing frames are, however, expensive. In most cases,investment in them is only worthwhile in cases where a spinning mill isbeing equipped with new machinery. Existing drawing frames cannot beconverted into regulated drawing frames usually for reasons of design.

SUMMARY OF THE INVENTION It is an aim of the present'invention toprovide a method and apparatus to overcome the problems anddisadvantages encountered heretofore.

The present invention provides a method of regularizing the output ofdrawing frames of the kind used in the spinning industry, wherein atleast one of the slivers delivered to the drawing frames is passedthrough a pair of cylinders whose rotational speed is controlled by ameasuring signal generated by a measuring element corresponding to theoverall cross-section of the output of the drawing frame.

The present invention also provides an apparatus for regularizing theoutput of a textile drawing frame, comprising an actual drawing anddrafting system as well as additional pair of cylinders having a drivewhich is controlled by a measuring element influenced by the output ofthe drawing frame with the additional rollers being arranged to subjectat least one sliver to a variable draft in regard to its cross-section.

The present invention is based on the recognition that, for regularizingthe output of drawing frames of the kind used in the spinning industry,a considerable textile-technological improvement is actually obtainedsimply by regulating out the prolonged fluctuations which are relativelylow in amplitude. Accordingly, it is only fairly minor changes in draft,amounting to a few percent of the total draft, which are required toregulate them by modifying the draft. In this manner, it is possible toobtain the same effect by a correspondingly greater change in draft ononly a proportion of the quantity of fibres passing through the drawingframe. For example, if in a drawing frame with six slivers arrivingalongside one another only one of these slivers is subjected to anadditional draft, it is still possible in theory to correct afluctuation in the quantity of fibres of up to i 8 percent correspondingto i A. 1/6.

The foregoing affords the advantage that the outlay in terms of designrequired for driving and controlling one or only a few slivers remainsmoderate and can also be subsequently applied to already existingunregulated drawing frames. It is also possible to eliminate in this waythe need to control sliver delivery because most of the fibres aredelivered to the drawing frame at a constant rate. The drive system of,in particular, the latest double-headed high-performance drawing frameswould have to be almost completely re-designed' because it is common toboth outputs although as a' result of regulation the rates at which theslivers are delivered can no longer be the same. However, individualslivers as provided by the present invention can readily be drawn offdirectly from a can. Since, in addition, deviations from the requiredcross-section are generally very small in practice, it is sufficient-foronly one or, two slivers to be regulated.

BRIEF DESCRIPTION OF THE DRAWING These and further objects, features andadvantages of the present invention will become more apparent from theaccompanying drawing which shows, for purposes of illustration only,several embodiments in accordance with the present invention andwherein:

FIG. 1 illustrates a drawing frame which is continuously regulated by anadditional pair of cylinders as compared with known frames,

FIG. 2 illustrates another drawing frame regulated in stages by twoadditional pairs of cylinders.

DETAILED DESCRIPTION OF THE DRAWING Referring now to the drawing and, inparticular, to FIG. 1, the reference numerals 3, 4, 5 denote pairs ofcylinders of a conventional multiple-cylinder drawing frame which,through suitably selected gear transmis sions, rotate at a constantspeed and hence exert a constant draft on the slivers 9 which arrivefrom beneath. The output 2 is combined in a condenser l and depositedinto cans in a known manner. A measuring element of the kind describedin US. Pat. No. 3,435,673 is accommodated in the condenser l andgenerates a pressure measuring signal which is at least substantiallyproportional to the quantity of fibres passing through the condenser 1.

According to the present invention, an additional pair of cylinders 6acts on the middle two slivers so that an additional drafting zone 7 isformed. This pair of cylinders 6 is driven by a variable speed motorarrangement 8, such as described in US. Pat. No. 3,l09,324. Adjustmentof this rotational speed is controlled by the pressure measuring signalin such a way that an excessive quantity of fibres in the condenser 1produces a reduction in the rotational speed, while a deficit of fibresin the condenser 1 produces an increase in rotational speed of the pairof cylinders 6. Conversion of the pressure measuring signal into theelectrical signal or other quantity required to control the rotationalspeed of the variable-speed motor arrangement 8 is carried out by knowntechniques of control engineering, such as by a pressure voltageconverter 10 of any conventional configuration.

This should accelerate or decelerate only relatively small rotatingmasses so that the performance and hence the dimensions of the controlelements can be kept small. To ensure that these regulated slivers,which can be very thin, are also safely engaged in the web 2, it isadvisable to deliver and regulate the slivers towards the middle ratherthan along the edges.

Instead of a continuous change in the rotational speed of the feedcylinders 6, it is also possible to use an intermittent system in caseswhere the demands, which the uniformity of output has to meet, are lessstringent. In this case, regulation is of course limited to the deliveryor non-delivery of a sliver. Since, as already mentioned, deviationsfrom the required crosssection are relatively small, a single correctionof this kind can be, sufficient in cases where the delivered sliver tobe regulated is considerably thinner than the other slivers.

A considerable improvement in the uniformity of output is actuallyobtained simply by delivering two slivers much thinner than usual,rather than one, intermittently to the drawing frame, asdiagrammatically illustrated in FIG. 2. Reference numerals 30 and 31 aretwo fairly thin slivers. In order to obtain an idea of their size, theycan each amount to three percent of the total cross-section of all theslivers and generally will fall within the range of 1 5 percent of thetotal quantity of fibers delivered to the drawing frame. In normalcases, one of the slivers, for example only the sliver 30, will arrive.It is delivered by way of the cylinder which in turn is driven by themotor or clutch 21. If the sliver is too thin, the cylinder 22 will alsobe rotated by the motor or clutch 23 so that the sliver 31 is alsodelivered. If the sliver is too thick, neither the band 30 nor thesliver31 will be delivered. In cases where for example the sliver 30 or31 makes up 3 percent of the overall cross-section, regulation will thusbe accurate to 1.5 percent. However, the requirement is that the overalldeviation should not be more than 4.5 percent. In practice, thisrequirement is often fulfilled, or can be produced again by way of analarm circuit which allows manual intervention.

While I have shown and described several embodiments in accordance withthe present invention, it is to be understood that the same issusceptible of numerous changes and modifications as will be apparent toone skilled in the art. I, therefore, do not wish to be limited to thedetails set forth herein but intend to cover all such changes andmodifications as are encompassed by the scope of the present invention.

What is claimed is:

1. An apparatus for regularizing the output of a textile drawing frame,comprising means for drawing and drafting a plurality of individualslivers including at least one pair of main cylinders driven at asubstantially constant speed, at least one pair of auxiliary cylindershaving 'drive means connected thereto for controllably rotating saidauxiliary cylinders, and a measuring element responding to the output ofthe drawing and drafting means for controlling said drive means, thepair of auxiliary cylinders being arranged to subject at least onesliver, but not all slivers, to a variable draft with respect to thecross-section thereof.

2. An apparatus according to claim 1, wherein the pair of auxillarycylinders is arranged in the middle of the drawing frame so as to act onat least a centrally arranged sliver of said plurality of individualslivers adjacent to one another for delivery to the drawing frame.

3. An apparatus according to claim 1, wherein said drive means includesmeans for continuously varying the rotational speed of the pair ofauxiliary cylinders in dependence upon a measuring signal generated bythe measuring element in response to the output of the drawing anddrafting means.

4. An apparatus according to claim 3, wherein the pair of auxillarycylinders is arranged in the middle of the drawing frame so as to act onat least a centrally arranged-sliver of a group of individual sliversadjacent to one another for delivery to the drawing frame.

5. An apparatus according to claim 1, wherein two pairs of auxiliarycylinders are provided, each of which is arranged to receive aparticular sliver, and said drive means includes means for controllingthe rotational speed of the cylinders in such manner that, on theoccurrence of a measuring signal corresponding to a total quantity offibers within a predetermined tolerance range, only one of the pairs ofauxiliary cylinders is driven at a predetermined rotational speed andthe other pair of stopped, while both pairs of auxiliary cylinders aredriven at a predetermined rotational speed when the measuring signalcorresponds to a total quantity of fibers below the predeterminedtolerance range, and both pairs of auxiliary cylindersare stopped whenthe measuring signal corresponds to a total quantity of fibers above thepredetermined tolerance range.

6. A method of regularizing the output of a drawing frame including atleast one pair of main drawing cylinders operating at a substantiallyconstant speed for use in the spinning industry, comprising:

deliveringa plurality of slivers to said pair of main drawing cylindersof the drawing frame;

drafting said plurality of slivers at a substantially constant speed;

condensing said plurality of drafted slivers;

detecting the density variation of the cross-sectional output of thecondensed sliver; and

changing the rate of feed of at least one, but not all,

of the slivers delivered to said main drawing cylinders in response tothe detected density variations of the cross-sectional output of thecondensed sliver. v

7. A method according to claim 6, wherein the step of changing the rateof feed of at least one, but not all, of the slivers includesselectively stopping at least two slivers, one sliver or none of theslivers in dependence upon whether the value of said density variationof the condensed sliver exceeds, is within or is less than apredetermined tolerance range, respectively.

8. A method according to claim 5, wherein the one sliver delivered at achanging rate has a fiber content per sliver of between about 1 percentand 5 percent of the total quantity of fibers delivered to the drawingframe.

9. A method according to claim 8, wherein said step of controlling therotational speed includes regulating the speed within a predeterminedtolerance range corresponding to the quantity of condensed fibers so asto regulate the speed in stages, whereby a constant quantity of fibersis added or retained when the density variation deviates from thetolerance range.

1. An apparatus for regularizing the output of a textile drawing frame,comprising means for drawing and drafting a plurality of individualslivers including at least one pair of main cylinders driven at asubstantially constant speed, at least one pair of auxiliary cylindershaving drive means connected thereto for controllably rotating saidauxiliary cylinders, and a measuring element responding to the output ofthe drawing and drafting means for controlling said drive means, thepair of auxiliary cylinders being arranged to subject at least onesliver, but not all slivers, to a variable draft with respect to thecrosssection thereof.
 2. An apparatus according to claim 1, wherein thepair of auxillary cylinders is arranged in the middle of the drawingframe so as to act on at least a centrally arranged sliver of saidplurality of individual slivers adjacent to one another for delivery tothe drawing frame.
 3. An apparatus according to claim 1, wherein saiddrive means includes means for continuously varying the rotational speedof the pair of auxiliary cylinders in dependence upon a measuring signalgenerated by the measuring element in response to the output of thedrawing and drafting means.
 4. An apparatus according to claim 3,wherein the pair of auxillary cylinders is arranged in the middle of thedrawing frame so as to act on at least a centrally arranged sliver of agroup of individual slivers adjacent to one another for delivery to thedrawing frame.
 5. An apparatus according to claim 1, wherein two pairsof auxiliary cylinders are provided, each of which is arranged toreceive a particular sliver, and said drive means includes means forcontrolling the rotational speed of the cylinders in such manner that,on the occurrence of a measuring signal corresponding to a totalquantity of fibers within a predetermined tolerance range, only one ofthe pairs of auxiliary cylinders is driven at a predetermined rotationalspeed and the other pair of stopped, while both pairs of auxiliarycylinders are driven at a predetermined rotational speed when themeasuring signal corresponds to a total quantity of fibers below thepredetermined tolerance range, and both pairs of auxiliary cylinders arestopped when the measuring signal corresponds to a total quantity offibers above the predetermined tolerance range.
 6. A method ofregularizing the output of a drawing frame including at least one pairof main drawing cylinders operating at a substantially constant speedfor use in the spinning industry, comprising: delivering a plurality ofslivers to said pair of main drawing cylinders of the drawing frame;drafting said plurality of slivers at a substantially constant speed;condensing said plurality of drafted slivers; detecting the densityvariation of the cross-sectional output of the condensed sliver; andchanging the rate of feed of at least one, but not all, of the sliversdelivered to said main drawing cylinders in response to the detecteddensity variations of the cross-sectional output of the condensedsliver.
 7. A method according to claim 6, wherein the step of changingthe rate of feed of at least one, but not all, of the slivers includesselectively stopping at least two slivers, one sliver or none of theslivers in dependence upon whether the value of said density variationof the condensed sliver exceeds, is within or is less than apredetermined tolerance range, respectively.
 8. A method according toclaim 5, wherein the one sliver delivered at a changing rate has a fibercontent per sliver of between about 1 percent and 5 percent of the totalquantity of fibers delivered to the drawing frame.
 9. A method accordingto claim 8, wherein said step of controlling the rotational speedincludes regulating the speed within a predetermined tolerance rangecorresponding to the quantity of condensed fibers so as to regulate thespeed in stages, whereby a constant quantity of fibers is added orretained when the density variation deviates from the tolerance range.